| Project/Area Number |
01550362
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
土木構造
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
MIKI Chitoshi Tokyo Institute of Technology, Dept. of Civil Eng., Professor, 工学部・土木工学科, 教授 (20016645)
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| Co-Investigator(Kenkyū-buntansha) |
TATEISHI Kazuo Tokyo Institute of Technology, Dept. of Civil Eng., Research Assoc., 工学部・土木工学科, 助手 (80227107)
MORI Takeshi Hosei University, Dept. of Civil Eng., Assistant Professor, 工学部・土木工学科, 講師 (10157860)
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| Project Period (FY) |
1989 – 1990
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| Project Status |
Completed (Fiscal Year 1991)
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| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1990: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1989: ¥1,500,000 (Direct Cost: ¥1,500,000)
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| Keywords | Welded Joint / Fatigue Strength / Fatigue Crack / Non-Destructive Evaluation / Ultrasonic Pulse Echo Inspection / Acoustic Emission / Undercutting / 溶接欠陥 / ポテンシャルドロップ法 / アコ-スティックエミッション法 / ル-トギャップ / 亀裂形状 / 鋼橋 / 疲労寿命 / 破壊力学 / 超音波探傷法 |
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| Research Abstract |
(1) Numerical simulation method of Ultrasonic Pulse-Echo Inspection, which potentially Is a powerful means for Non Destructive Evaluation of cracks and flaws of steel structures, is built. Through this simulation, the diffracting and reflecting waves at the voids and the slit are investigated in detail. Furthermore, suitable observation points to distinguish the shape of flaws from reflected waves are investigated.
(2) Fatigue tests are carried out on CCT specimens and fillet welded specimens with Acoustic Emission (AE) method to observe the behavior of crack initiate stage and propagate stage. It is observed that crack Initiate stage exists even for a welded joints In the same way for materials, and relatively intense AE signals occur in this stage.
(3) Fatigue tests are carried out on fillet welded joint specimens containing undercuttings of which dimensions are measured in detail. The effects of size and shape of undercuttings on the fatigue strength are Investigated. Besides, FEM analysis Is carried out on the model containing the undercuttings to calculate stress concentration at the bottom of undercuttings.
(4) For the case that crack initiates from welded root, the fatigue strength of load-carrying fillet welded joints Is investigated through experimental and analytical approaches. the length of non-penetrate section of weld root much influences on fatigue strength.
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